Permanent magnet type rotating machine

ABSTRACT

A permanent magnet type rotating machine comprises a cylindrical yoke; a plurality of permanent magnets installed on an inner periphery of the cylindrical yoke; a rotor rotatably installed at an inner peripheral portion of the plurality of permanent magnets; and a retaining portion provided at a conventional constituent member of the permanent magnet type rotating machine to elastically retain the plurality of permanent magnets in an axial direction.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a permanent magnet type rotatingmachine employing permanent magnets as field magnetic poles.

2. Discussion of Background

FIGS. 34 through 36 are diagrams showing a magnet fixing device of aconventional small-sized motor disclosed, for instance, in JapaneseExamined Utility Model Publication No. 38733/1973, wherein FIG. 34 is apartially broken front diagram, FIG. 35 is a partially broken sidediagram of FIG. 34, and FIG. 36 is a diagram showing an elastic fixingplate 10 in FIG. 35.

In FIGS. 34 through 36, reference numeral 1 designates a motor housing(yoke), to an end portion of which a bearing metal 2 is press-fixed by apress-fixing plate 3. Numeral 4 designates a plurality of fixing pieceswhich are cut out to the inner side of the motor housing 1, each ofwhich is provided with an angle α to retain ones of tapered portions 7and 8 which are formed at both ends of arcuate magnets 5 and 6. Theinner diameter B of the fixing piece 4 is formed larger than an innerdiameter C which is formed by the arcuate magnets 5 and 6. Numeral 9designates protrusions which are protruded to the inner side of themotor housing 1, for positioning the arcuate magnets 5 and 6 in thecircumferential direction. Numeral 10 designates a ring-like elasticfixing plate, which is formed by an elastic material such as steel platefor spring and phosphor bronze plate for spring, at the inner side ofwhich a plurality of press-fixing claws 11 are provided for retainingthe other tapered portions 8 of the arcuate magnets 5 and 6, and at theouter diameter portion of which a plurality of fixing claws 12 areprovided for fixing the elastic fixing plate 10 to the housing 1 inpress-fitting the elastic fixing plate 10 to the motor housing 1 in apress-fitting operation. Further, the fixing claw 12 is inclined towardthe outside of the magnet by an angle of θ with respect to a plane 13 ofthe elastic fixing plate 10. The outermost diameter D of the fixing claw12 is formed slightly larger than the inner diameter A of the motorhousing, and the inner diameter E thereof that is the same with theinner diameter of the press-fixing claw 11, is formed larger than theinner diameter C of the magnets 5 and 6.

An explanation will be given of the integrating operation of the magnetfixing device in the above construction. First, the bearing metal 2 ispress-fixed to one end portion of the motor housing 1 by thepress-fixing plate 3. Next, the arcuate magnets 5 and 6 are inserted tothe inner diameter portion of the motor housing 1 along the positioningprotrusions 9. Then, the tapered portions 7 are retained by the fixingpieces 4. Further, the elastic fixing plate 10 is finally press-fittedto the inner diameter portion of the motor housing by a pertinentpressure, and the press-fitting is stopped when the press-fixing claws11 apply a pertinent pressure on the tapered portions 8 of the magnets 5and 6.

As stated above, in the conventional permanent magnet type rotatingmachine, the permanent magnets 5 and 6 are fixed in the axial directionby the elastic fixing plate 10 which has been press-fitted and fixed inthe yoke 1. Accordingly, the elastic fixing plate 10 for fixing thepermanent magnets 5 and 6 in the axial direction is necessary as anadditional member, which increases the number of parts and increases theproduction cost.

SUMMARY OF THE INVENTION

It is an object of the present invention to solve the above problems andto provide a permanent magnet type rotating machine which positions andfixes the permanent magnets in the axial direction without increasingthe number of parts thereby achieving the cost reduction.

According to an aspect of the present invention, there is provided apermanent magnet type rotating machine comprising:

a cylindrical yoke;

a plurality of permanent magnets installed on an inner periphery of thecylindrical yoke;

a rotor rotatably installed at an inner peripheral portion of theplurality of permanent magnets; and

a retaining portion provided at a conventional constituent member of thepermanent magnet type rotating machine to elastically retain theplurality of permanent magnets in an axial direction.

According to the aspect of the present invention, an additional memberis not necessary for fixing the permanent magnets in the axialdirection, since the retaining portion is provided at a conventionalconstituent part.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an axially divided sectional diagram of important partsshowing Example 1 of the invention;

FIG. 2 is a sectional diagram (excluding a plate) viewed from the lineII--II of FIG. 1;

FIG. 3 is a diagram viewing FIG. 2 from the rear side;

FIG. 4 is an axially divided sectional diagram of important partsshowing Example 2 of this invention;

FIG. 5 is a partial perspective view showing a ring-like elastic memberof FIG. 4;

FIG. 6 is an axially divided sectional diagram of important partsshowing Example 3 of this invention;

FIG. 7 is a sectional diagram viewed from the line VII--VII of FIG. 6;

FIG. 8 is an axially divided sectional diagram of important partsshowing Example 4 of this invention;

FIG. 9 is a partial perspective view showing a plate in FIG. 8;

FIG. 10 is an axially divided sectional diagram of important partsshowing Example 5 of this invention;

FIG. 11 is an axially divided sectional diagram of important partsshowing Example 6 of this invention;

FIG. 12 is an axially divided sectional diagram of important partsshowing Example 7 of this invention;

FIG. 13 is a sectional diagram of the front side of a starter showingExample 8 of this invention;

FIG. 14 is a perspective view showing a lever packing in FIG. 13;

FIG. 15 is a sectional diagram of the rear side of a starter showingExample 9 of this invention;

FIG. 16 is a partial perspective view showing a brush holder in FIG. 15;

FIG. 17 is a sectional diagram of the rear side of a starter showingExample 10 of this invention;

FIG. 18 is a partial perspective showing a rear bracket in FIG. 17;

FIG. 19 is a sectional diagram of important parts of a starter showingExample 11 of this invention;

FIG. 20 is a partial perspective view showing a center bracket in FIG.19;

FIG. 21 is an axially divided sectional diagram of important partsshowing Example 12 of this invention;

FIG. 22 is a diagram showing another Example of FIG. 21;

FIG. 23 is a sectional diagram of important parts showing Example 13 ofthis invention;

FIG. 24 is a diagram showing another Example of FIG. 23;

FIG. 25 is a perspective view of a holder showing Example 14 of thisinvention;

FIG. 26 is a sectional diagram showing an Example in use of the holderin FIG. 25;

FIG. 27 is a diagram showing another Example of FIG. 26;

FIG. 28 is a half sectional perspective view showing Example 15 of thisinvention;

FIG. 29 is a development diagram viewing FIG. 28 from the opening side;

FIG. 30 is a sectional diagram viewed from the line XXX--XXX of FIG. 29;

FIG. 31 is a sectional diagram viewed from the line XXXI--XXXI of FIG.29;

FIG. 32 is a half sectional perspective view showing Example 16 of thisinvention;

FIG. 33 is a half sectional perspective view showing Example 17 of thisinvention;

FIG. 34 is a partially broken front diagram showing a conventionaldevice;

FIG. 35 is a partially broken side diagram of FIG. 34; and

FIG. 36 is a diagram showing an elastic fixing plate in FIG. 35.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS EXAMPLE 1

An explanation will be given of an embodiment of this invention inreference to FIGS. 1 through 3. FIG. 1 is an axially divided sectionaldiagram of important parts, FIG. 2 is a sectional diagram (excluding aplate) viewed from the line II--II of FIG. 1, and FIG. 3 is a diagramviewing FIG. 2 from the rear side (front side of motor).

In FIGS. 1 through 3, reference numeral 14 designates an armature, 16, acylindrical yoke made from a steel plate, 17, a bracket fitted to anopening portion of the yoke 16, 18, permanent magnets composing fieldmagnetic poles, 19, a punched-out portion formed in the yoke 16, and 20,an internal gear of a planetary gear speed reducing mechanism, which isfixed to the bracket 17. Numeral 21 designates a retaining portion whichis integrated to the internal gear 20 in use of an elastic material, andwhich is protruded so as to press an end face 18a of the permanentmagnet 18. Numeral 22 designates a plate fixed to the internal gear 20,which is provided for dust proof and oil proof against dust or oil fromthe contiguous planetary gear device and the like. As shown in thesediagrams, in a state wherein the permanent magnets 18 are installed, thepermanent magnets 18 are pressed by the elastically deformed retainingportions 21 in the axial direction and are positioned and fixed betweenthe punched-out portion 19 and the retaining portions 21. Therefore, thepermanent magnets 18 are fixed in the axial direction by a conventionalconstituent member of the internal gear 20.

EXAMPLE 2

In the above Example 1, the retaining portion 21 is integrated to theinternal gear 20. However, as shown in FIGS. 4 and 5, the retainingportions 21 may be provided at a separate ring-like elastic member 23,which is fixed to the internal gear 20. In this case, the internal gear20 can be formed by a metal or a synthetic resin (for instance,plastics).

EXAMPLE 3

In the above Examples 1 and 2, the retaining portions 21 are provided onthe side of the internal gear 20. However, as shown in FIGS. 6 and 7,the retaining portions 21 are integral with the dust proof and oil proofplate 22 in use of an elastic material. The plate 22 which is aconventional constituent member, is, for instance, a pressed product ofsteel plate that causes an elastic force by the steel plate on theretaining portions 21.

EXAMPLE 4

In the above Example 3, the retaining portions 21 are integrated to theplate 22. However, as shown in FIGS. 8 and 9, the retaining portion maybe composed of a plurality of elastic members 24 which are fixed to theplate 22 by connecting means such as welding, eyeleting and riveting.

EXAMPLE 5

In the above Examples 1 and 2, the retaining portion 21 is provided onthe side of the internal gear 20 and the internal gear 20 directly maycontact the bracket 17 in the axial direction. However, as shown in FIG.10, a portion 20a of the internal gear 20 may contact the end face 18aof the permanent magnet 18, and an elastic body (gummy packing, spring,beleville spring, etc.) 25 may be inserted between the internal gear 20and the bracket 17 thereby pressing the permanent magnets 18 by theportion 20a of the internal gear 20. Also in this case, the internalgear 20 may be formed by a metal or a plastics as in the conventionalcase.

EXAMPLE 6

In the above Examples 3 and 4, the retaining portions 21 are provided onthe side of the plate 22 and the plate 22 directly contacts the internalgear 20. However, as shown in FIG. 11, a portion 22a of the plate 22 maycontact the end face 18a of the permanent magnets 18, and the elasticbody 25 may be inserted between the plate 22 and the internal gear 20thereby pressing the permanent magnets 18.

EXAMPLE 7

In the above Example 6, the portion 22a of the plate 22 directlycontacts the permanent magnet 18. However, as shown in FIG. 12, aportion 25a of the elastic body 25 may contact the end faces 18a of thepermanent magnets 18 thereby pressing the permanent magnets 18.

EXAMPLE 8

Next, an explanation will be given of a case wherein a lever packing isemployed as a conventional constituent member in reference to FIGS. 13and 14. In FIGS. 13 and 14, reference numeral 26 designates an armatureshaft of a direct current motor, 27, an iron core of an armature, and28, an overrunning clutch, which is provided with a pinion in mesh witha ring gear of an engine, not shown. Numeral 29 designates anelectromagnetic switch, and 30, a shift lever which is operated by theelectromagnetic switch 29, and which moves the overrunning clutch 28 andthe pinion in the axial direction in starting the engine. Numeral 31designates a resilient lever packing which is provided between a fulcrum30a of the shift lever 30 and the yoke 16, and 32, protrusions which arethe retaining portion, and which are integrated with the lever packing31 through a ring-like member 33.

In a state wherein the lever packing 31 is installed by the bracket 17,as shown in FIG. 13, the protrusions 32 press the end faces 18a of thepermanent magnets 18. Therefore, the permanent magnets 18 can be fixedin the axial direction.

EXAMPLE 9

An explanation will be given of a case wherein a brush holder isemployed as a conventional constituent member in reference to FIGS. 15and 16. In FIGS. 15 and 16, numeral 34 designates a rear bracket, 35,commutator brushes, and 36, a brush holder which is integrated with theretaining portions 21.

In a state wherein the brush holder 36 is installed, the retainingportions 21 contact end faces 18b of the permanent magnets 18 and pressthe permanent magnets 18 by their elastic forces. Therefore, thepermanent magnets 18 can be fixed in the axial direction.

EXAMPLE 10

In the above Example 8, the retaining portions 21 are integrated to thebrush holder 36. However, as shown in FIGS. 17 and 18, the retainingportions 21 may be integrated to the rear bracket 34.

EXAMPLE 11

Next, an explanation will be given of a case wherein a center bracket isemployed as a conventional constituent member in reference to FIGS. 19and 20. In FIGS. 19 and 20, reference numeral 37 designates a centerbracket interposed between the yoke 16 and the front bracket 17, whichis resilient and which is integrated with protrusions 37a, the retainingportions, that is made of, for instance, chloroprene gum.

In a state wherein the center bracket 37 is installed, the protrusion37a contact the end faces 18a of the permanent magnets 18 and press thepermanent magnets 18 in the axial direction by their elastic forces.Accordingly, the permanent magnets 18 are fixed in the axial direction.

EXAMPLE 12

In the above Examples 1 through 11, the punched-out portion 19 in theyoke 16 is shown as a member for positioning the end faces 18a or 18b ofthe permanent magnets 18. However, as shown, for instance, in FIG. 21,the punched-out portion 19 may be substituted by a difference in level19a, or a thickened portion 19b of the yoke 16 as shown in FIG. 22.

EXAMPLE 13

In the above Examples 1 through 12, only the fixing of the permanentmagnet 18 in the axial direction is shown. By contrast, an explanationwill be given of the fixing of the permanent magnet 18 in thecircumferential direction in reference to FIGS. 23 and 24.

In FIG. 23, the permanent magnet 18 is positioned and fixed between apunched-out portion 38 of the yoke 16 and a commutating pole which isfixed to the yoke 16 by welding. In FIG. 24, the permanent magnet 18 ispositioned and fixed between two of the punched-out portions 38.

EXAMPLE 14

When a holder 40 which is provided with an elasticity by bending aphosphorus bronze plate as shown in FIG. 25, is used in the aboveExample 13, the punched-out portion 38 and the commutating pole 39 maypreviously be arranged as shown in FIG. 26 and afterwards, the permanentmagnet 18 may be fixed by the holder 40. Further, as shown in FIG. 27,two of the punched-out portions 38 may previously be arranged andafterwards, the permanent magnet 18 and the commutating pole 39 may befixed by the holder 40. Accordingly, the integrating operationalperformance can be improved.

EXAMPLE 15

Next, an explanation will be given of other Examples of this inventionin reference to FIGS. 28 through 31. In FIGS. 28 through 31, referencenumeral 41 designates a cylindrical yoke, 42, a plurality (six in thedrawings) of permanent magnets installed on the inner peripheral face ofthe yoke 41 and 43, a bent portion connected to a rear side cylinderopening 41a of the yoke 41, which is provided with punched-out portions43a at positions corresponding to the widths (each of which is a widthincluding that of a commutating pole 44 in the drawing) of the permanentmagnet 42. Reference numeral 45 designates a holder plate which isattachably and detachably fixed to a front side cylinder opening 41b ofthe yoke 41, and which is provided with bent spring portions 45apressing the permanent magnets 42 in the axial direction, and spacers45b positioning the permanent magnets 42 in the circumferentialdirection. As shown in FIG. 31, the holder plate 45 is fixed to the yoke41 by press-fitting holes 45c to punched-out portions 41c of the yoke41.

The holder plate 45 is provided for the purpose of dust proof, greaseseal or the like against dust from a contiguous clutch or the like onthe front side, which is one of the conventional constituent members.

Finally, when the holder plate 45 is fixed to the yoke 41 by insertingthe holder plate 45 in the direction of an arrow mark 46 in FIG. 28, thepermanent magnets 42 can be fixed between the bent portion 43 and theholder plate 45 by pressing the permanent magnets 42 in the axialdirection by the bent spring portions 45a, and also the permanentmagnets 42 can be positioned in the circumferential direction by thespacers 45b and the bent portions 43a.

In this way, the fixing of the permanent magnets 42 in the axialdirection and in the circumferential direction can be performed in onemotion by the holder plate 45 which is fitted in the yoke 40. Therefore,the total axial length does not increase more than the conventionalcase. Further, the integrating operation can be performed only byfitting, inserting and fixing the holder plate 45 into the yoke 41, andtherefore, the operational performance is improved. Further, thecommutating pole 44 does not have to be welded to the yoke 41, and theinvention can handle a case wherein there is no commutating pole 44.

EXAMPLE 16

In the above Example 15, the punched-out portions 43a formed on the bentportion 43 of the yoke 41 may not be provided and the construction maybe as shown in FIG. 32. In this case, the positioning of the permanentmagnets 42 in the circumferential direction can be maintained byincreasing the spring forces of the bent spring portions 45a of theholder plate 45, which facilitates the working operation by dispensingwith the punched-out portions 43a.

EXAMPLE 17

In the above Example 15, the bent portion 43 of the yoke 41 is formed atall the circumferential portion of the yoke 41. However, the bentportion 43 may be formed in a form of a sideway channel at parts of thecircumferential portion. In this case, the fixing of the permanentmagnets 42 on the rear side can be performed more firmly.

As stated above, this invention provides an effect wherein the permanentmagnets can be positioned and fixed in the axial direction withoutincreasing the number of parts thereby achieving the cost reduction.

What is claimed is:
 1. A permanent magnet type rotating machinecomprising:a cylindrical yoke; a plurality of permanent magnetsinstalled on an inner periphery of said cylindrical yoke; a rotorrotatably installed at an inner peripheral portion of said plurality ofpermanent magnets; a plate having an outer peripheral portion disposedproximate to said cylindrical yoke and having an inner peripheralportion disposed proximate to a rotating shaft of said rotor; and aretaining portion integrally provided on said plate to elasticallyretain said plurality of permanent magnets in an axial direction.
 2. Apermanent magnet type rotating machine comprising:.a cylindrical yokehaving a punched-out portion; a plurality of permanent magnets installedon an inner, periphery of said cylindrical yoke; a rotor rotatablyinstalled at an inner peripheral portion of said plurality of permanentmagnets; and a retaining portion integrally provided on a singleconstituent member of said permanent magnet type rotating machine toelastically retain said plurality of permanent magnets in an axialdirection wherein said plurality of permanent magnets are, pressed bysaid retaining portion in an axial direction and are positioned andfixed between said punched-out portion and said retaining portion.